A mouse line has been generated in which the Dlx-2 gene was disrupted by homologous recombination. This gene plays a role in normal distribution of cranial neural crest cells that are involved with development of cranial structures including skeletal structures, vascular structures and muscles. The homozygous knockout mice die shortly after birth making it difficult to establish a line of these mice. Affected animals are therefore rare and techniques like MR microscopy are very useful for observing their maldevelopment since the specimen is not consumed by the procedure. We propose to scan ( 9 Tesla) embryos between gestational days 12 and newborns to determine which tissues are affected by this gene knockout. These results will help us to infer the role of the Dlx-2 gene in normal development.